Pipe coil



March 19, 1935. R K. HcJPK-INS PIPE COIL Filed Dec. 20, 1932 Erm NEE @En @En q y@ l/O INV TOR my( a/@wf BY ATTORN EY Patented Mar. 19, 1935 Y UNITED-'STATES rATsNr orFinE M. W. Kellogg Co., New York, N. Y., a corporation of Delaware Application pece'mber 20,1932, serial No. 648,957 5 claims. (ol. 19e- 133)V This invention 'relates to pipe coils and in `parwill be best appreciated from a consideration off ticular to pipecoils of the character used in conthe following description'` taken together with'the nection with the conversion, or cracking of high accompanying drawing in which; if i. boiling point hydrocarbon oils to low boiling Fig. 1 shows aside elevation of a pipe coil,

point hydrocarbon oils and similar processes; LFig. 2 isa sectional elevation taken Von line 22 5 In the cracking of petroleum oils, as at present of `Figure 3, and f practiced, it isv not unusual to circulate fluids Fig. 3 is a part'sectional plan taken online 3,-3 through pipe coilsat pressures as high at 1100 of Figure 2. ,f pounds per square inch and at temperatures as', The coil, 10 is made up of a plurality of pipe Vhigh. as 1100o F. vSince the fluids circulated lengths li `connected by clamps l2 to goose neck 10 usually carry along with them solid particles,` headers 13 to form the desired fluid path.\v The such as` carbon, 'and contain corrosive impurities, fluid circulated jthrough coil 10 enters through such as sulphur, the diminution of the walls of pipe 14 and exits through' pipe'l. the coils is rapid even at moderate velocities of As best sho-wn in Figures 2 and 3 pipes 11 are' 15' flow of the uids through the coils.` The diminuprovided with flanges 16- at each end'thereof. 15l

tion or Wearing away of the walls'ofthe coils is Goose neck headers 13 are also provided `with believed to be caused bythe combined eifect' of flanges 16 similar to those of pipes 11. Flanges erosion, due tothe entrained'solid particles, land*` 16 have circular grooves cut in 'their faces to corrosion, due to the corrosive impurities of the accommodate therein gaskets 17. Each of fluids circulated. The diminution is appreciable clamps 12 comprises semi-circular pieces 18 and 20 throughout the coil but is especially Vnoticeable 19, having. lugs at'each endprovided with holes at the headers Yconnecting the straight lengths of therein for the passage of bolts 20. The central the coils. Thus, in o-rder to provide safe coils inner portion of pieces 18 and'19'are cut away of reasonably long life it has become the 'practice to provide semi-circular recesses adapted to "'to make the component parts of the coils out of house'anges V16. The arrangement is such that 25- special alloys such as tungsten-iroi'i,` chromium when`bolts'20'a`re tightened, the corners of the iron, etc., alloys. Coils made of these alloys are recesses of the pieces 18 and 19 move up on the satisfactory, but very expensive. A incline faces of fiangesul' to force theanges I have found that I can obtain at leastas satistoward each otherl and by reason of gaskets 1"!V 305 factory results as are obtained 'by' the use of form afl'uid'tight joint. Asshown by heavy lines expensive alloys at only a fraction of the cost. 21, the surfaces of the pipe lengths 11 and goose In accordance with my invention I provide a coil neck headers 13 normally exposed to the fluid the component parts of which are made upv of circulatedthro-ugh the coil l0 are coated with acarbon steel or similar material and have the baked enamel.

surfaces normally exposed to the fluids circulated p Pipe lengths 11 and goose neck headers-13 are 35 therethrough coated with a baked enamel of made of carbon steel or similar low priced metal smooth glass like finish. Preferably I choose an and Vare formed to the desired size in accordance enamel which is highly resistant to the corrosive with the usual practice, the walls of pipe lengths components of the fluids circulated and which 11 and goose neck headers 13 being made of the has a coefficient of expansion substantially equal thickness necessary to withstand the pressures 0 to that of the steel. of the coil. The resistant for which coil lo is designed and the. inside diam-` character of the enamel assures the corrosive eter of pipe lengths l1 and goose neck headers 13 eiect due to the corrosive impurities in the fluid being made somewhat larger than called for in being kept at a minimum. Because of the order to allow for enamel coating 21.

smooth glass like finish of the enamel the resist- The inner surfaces of pipes 11 and goose neck 45 ance to flow through the coil is appreciably deheaders 13 as well as the faces of flanges 16, inside creased with a consequent decrease in the turbuof the circular grooves which are adapted to lence at Vthe headers. Since the finish is not only accommodate gaskets 17, are then coated with glasslike, but continuous and practically void of frit. The frit chosen being such that it will pores, pits etc., the tendency of the solid particles produce an enamel of smooth glass like nish,

to accumulate on the walls and thus form eddy substantially devoid of holes, bubbles, pores and currents producing obstructions which are largely the like, and resistant to the corrosive action of responsible for erosion, is reduced to a minimum the corrosion impurities of the fluid. The enalso. amel produced also having a coeflicient of ex- Other objects and advantages of my invention pansion substantially equal to that of the carbon 5? steel, or other material, out of which pipe lengths 11 and goose neck headers 13 are made. The frit may be blown onto the surfaces to be coated in the powder form, or it may be applied thereto as a water suspension. After the frit has been applied pipes 11 and goose neck headers 13 are then allowed to stand until the frit is dried, after which the frit is brushed oi or otherwise removed from any surface which it is not intended to enamel. The coated parts of the coil 10 are then placed in a suitable furnace and subjected to temperatures ranging from 1300 to 1700 F. and are allowed to remain at these temperatures until the frit has fused and an enamel of propercharacter has been produced. The parts are then removed from the furnace and the coil is ready for assembly.

It is to be noted that coil 10 *made up of enameled carbon steel, pipe lengths 1'1 and goose neck headers 13 is in every way as strong as a similar coil made up of expensive alloy headersand-pipe lengths. Furthermore, coil 10 is less subject to erosionv and corrosion by reason of the vcorrosion resistant qualities and the smooth glass like finish of the enamel. Also, since solid particles entrained in the iluid circulated throughcoil10 do not have the tendency to stick to the glass-like surfaces of coil 10 the erosion due to eddy currents is practically eliminated.. It is also to be noted that because of enamel coating 21 they erosion and corrosion does not reduce the metal walls of coil 10. shows that enamel coating 21 is badly worn a new enamel coating may be baked on and coil 10 made, the equal in every way to anew coil. v

I claim:

A pipe coil for cracking hydrocarbon under high `pressure and heat, comprising a coil made up of a plurality of pipe lengths and header means for connecting the ends of said pipe lengths to forma continuousuid path, the inner surfaces of said pipe lengths and headers beingr coated with a corrosion resistant vitreousenarnel having'smooth glass like finish.

2. lA pipe coil for cracking hydrocarbon under high pressure and heat, comprisingv a plurality of carbon steel pipe lengths, carbon steel header means for connecting the ends 'of saidv pipe lengths to form a continuous fluid path, the inner surfaces of said pipe lengths :and said header means being coated with albaked on vitreous-enamel of smooth glass-like nish, said enamel coating having a coecient of expansion HenceY when inspection substantially equal to that of the steel of Ysaid pipe lengths and said header means.

3. A pipe coil for cracking hydrocarbon under high pressure and heat, comprising a plurality of pipe lengths having flanges at each end thereof, header means having flanges at the endsthereof, adapted to cooperate with the flanges of said pipe lengths and means for connecting the anges of said pipe'lengthsto the llanges Yof said header means to form a continuous fluid path, said pipe lengths and said header means having the portions of their surfaces normally exposed tothe fluid-circulated through said coil coatedv with a Ycorrosion resistant vitreous enamel of smooth glass like nish whose coefficient of expansion is substantially equal to the coefficient of expansion of the material of said pipe lengths and said header means. v

4. A ppi-pe coil for cracking hydrocarbon under high pressure andheat, comprising a plural/ity of parallelly arranged pipe lengths having flangesv at each end thereof, headers having ilanges'at each end thereof, adapted to cooperate withsaid t pipe lengths to forma continuousY fluidgpzaitli,"Y

packing means between the flangesrof Ysaid pipe lengths and they flangesv of said headers, "means for joining the flanges of said ,pipe lengths the flanges of saidfheaders in uid tight relation, the surfaces of said pipe lengths and said headers; defining the fluidpath through said rcoil being coatedwith a corrosion resistant vitreous enamel of smooth glass like finish whose coecientof expansion is substantially equal tothatof the material ofsaid pipe lengths, and said headers.

5. A pipe coil for cracking hydrocarbon under high pressure andheat, comprising a plurality'of parallelly arrangedjcarbon steel pipe .lengthsu having ilangesateachend thereof, carbon steel. headers having `flanges `at each end thereof. adapted tocooperate with said pipe lengths 'to form a continuous lluid path, packing meansbefl tween the flanges of `said pipe lengths and the flangesof said headers, and means for joining the anges of said pipe lengths andthe flanges of said headers in fluid tight relation, the 'surfaces-l of said pipe lengths and said headers defining' the fluid paths through'said coil beingv coated with a corrosion resistant vitreous enamel ofl smoothV glass `like finish, whoseV coeilicient of expansion issubstantiallyrequal to that of lthesteel of said pipe lengths and said headers.

ROB'ERT K. HOPKINS. 

